Method for logging wells



April 3, 1956 s. E. BUCKLEY ETAL METHOD FOR LOGGING WELLS Filed Dec. 17, 1954 2 Sheets-Sheet 1 INVENTORS. S/uar E. Buck/ey, Wh/'lman D-Mounce.

A T TOR/VE' Y- April 3, 1956 s. E. BUcKLEY ETAL 2,740,695

METHOD FOR LOGGING WELLS Filed Dec. 17, 1954 2 Sheets-Sheet 2 IN VEN TORS.

Stuart E. Buck/ey, BY Whitman D. Moz/nce.

A TTOR/VEK United States Patent O METHOD FOR LOGGING WELLS Stuart E. Buckley and Whitman D. Mounce, Houston, Tex., assignors, by mesne assignments, to Esso Research and Engineering Company, Elizabeth, N. J., a corporation of Delaware Application December 17, 1954, Serial No. 476,044

4 Claims. (Cl. 23-230) The present invention is directed to a method for detecting the presence of a petroliferous substance in an earth formation penetrated by a well bore. More particularly, the invention is directed to prospecting a well bore penetrating an earth formation containing hydrocarbons and other carbonaceous matter.

This invention is a continuation-impart of our co-pending application Serial No. 285,223, led April 30, 1952, and now Patent 2,708,155, entitled Method for Logging Wells."

The present invention may be briefly described as involving the introduction into a well bore penetrating an earth formation of an oxidizing agent reactable with hydrocarbons or other carbonaceous matter in said formation and contacting the oxidizing agent with the formation containing the hydrocarbons or other carbonaceous matter. The reaction between the oxidizing agent and the petroliferous substance or hydrocarbon in the formation causes the generation of heat and the generation of an elastic wave, such as a sound wave or a pressure impulse. The formation of heat or the generation of an elastic wave may be detected by thermometric methods or acoustical methods or by pressure indicating devices at the earths surface which allows the presence of hydrocarbons to be indicated directly. Since the oxidizing reaction between the oxidizing agent and the hydrocarbon or petroliferous substances in the formation being tested may form oxidation products such as carbon dioxide, carbon monoxide and acids, the presence of such hydrocarbons may also be indicated chemically. In short, when carbon monoxide and carbon dioxide are formed, the presence of such gases may be determined chemically by means well known to the chemist and the presence of hydrocarbons in the formation thus be determined. Likewise, the oxidation of hydrocarbons or petroliferous substances in or adjacent the formation by the oxidizing agent may cause the formation of acids which likewise may be determined chemically by titration or may be indicated by potentiometric methods. In any event it is contemplated in the practice of our invention that the reaction will cause one or more effects which may be detected and displayed whereby the presence of hydrocarbons in the formation is indicated.

In the practice of our invention it is possible to employ as oxidizing agents, oxidizing agents from a large number of materials which are known to react with hydrocarbons. Among these known oxidizing agents reactable with hydrocarbons are chlorine, perchloric acid, liquid oxygen, air, hydrogen peroxide, chlorosulfonic acid, iluorosulfonic acid and the like. It is also possible to use the other perhalogen acids, such as perfluoric acid, per-iodio acid and perbromic acid. Other oxidizing agents which may be suitable in the practice of the present invention are a mixture of nitrogen dioxide and aniline, potassium permanganate, chlorine, aqua regia, and the like. When chlorine is employed, it will be necessary to employ a catalyst therefor. For example, red

phosphorus in a finely divided condition may be dispersed in the liquefied chlorine. Likewise when the perhalogen acids are employed, it will be desirable to use a catalyst to cause the oxidation reaction to proceed spontaneously at a temperature such as that encountered in a well bore. For example, it is possible to employ perchloric acid having a strength in the range from to 84% HClO4 and temperatures down to as low as 40 C. by using a catalyst such as ceric ammonium nitrate. Other catalystsmay be employed such as, for example, ammonium vanadate and osmium tetraoxide.

The temperature to be employed in the practice of the present invention wherein a petroliferous substance in a formation is caused to react with an oxidizing agent may range from substantially less than 30 C. up to about 500 C. Pressures may range from the pressure normally found in a well bore, where hydrocarbons are encountered, up to pressures as high as 20,000 pounds per square inch.

The invention may be practiced by introducing an oxidizing agent into contact with an earth formation penetrated by a well bore. This may be done suitably by disturbing or disrupting the filter cake which ordinarily sheaths the permeable sections of the well bore. By disrupting the filter cake the formation is exposed which may or may not contain hydrocarbons. The oxidizing agent is then introduced directly into contact with the exposed face of the formation and the reaction caused to proceed. The oxidizing agent selected will determine whether or not it will be necessary to apply heat at the point where the oxidizing agent is contacted with the formation. By employing perchloric acid of a suitable strength of HClO4 reaction may be obtained at temperatures as low as 40 C. At a temperature of 150 C. the reaction proceeds with moderate speed and at a temperature of C. the reaction between perchloric acid and hydrocarbons is violent. Actually lower temperatures than 40 C. may be encountered in an earth formation and we do not intend to limit ourselves by such temperatures as recited. The temperature of the earth formation may be substantially less than 30 C. Thus, the temperature necessary to initiate the reaction may be reduced by employment of suitable catalysts. For example, by use of ceric ammonium nitrate dissolved in Water and added to the perchloric acid it is possible to obtain an explosive reaction at temperatures as low as 40 C.

The invention will be further illustrated by reference to the drawing in which:

Figs. l and lA illustrate an embodiment in partial section suitable for practice of our invention with Fig. 1A being a continuation of Fig. l;

Fig. 2 is an enlarged view in partial section of a detail of Fig. l; and

Fig. 3 is a detailed sectional view of a seismometer suitable for use in the practice of our invention.

In the several figures of the drawing, identical numerals will be employed to designate identical parts.

Referring now to Figs. l, 1A and 2, numeral 11 designates a well bore in an earth formation 12 which is lined with a filter cake 13 resulting from drilling operations employing a conventional type of drilling mud. Arranged in the well bore 11 is a body member 14 which is suspended from a well head, not shown, by a cable 14a which may be, and in this particular instance is, an electrical conductor cable. The body member 14 may be positioned adjacent a wall of the well bore as is shown in the drawing.

The body member 14 is provided with a piston cylinder 15 which may be formed integrally with the body member 14 but preferably is bored in a block member 16. Arranged within the piston cylinder 15 is a piston 17 which is provided on a free end thereof with a deformable seal- 3 ing member 18, the function of which will be described in more detail hereinafter. It will be noted that the block 16 is provided with an enlarged portion 19 and that a cavity 20 is dened by the enlarged portion 19 to accommodate the deformable sealing member 18 as the piston member 17 moves in the piston cylinder 15.

The body member 14 has -arranged within it an exhaust reservoir 21, a hydraulic fluid reservoir 22, a first piston cylinder 23 and a second piston cylinder 24. The body member 14 also has arranged within it a cavity 25 and a chamber 26 which is adapted to contain a tiuid oxidizing agent.

Arranged in the body member 14 above the hydraulic fluid reservoir 22 and below the block member 16 i-s a piston cylinder 27 which allows the piston 17 to be moved by the effect of the drilling mud pressure on the hydraulic fluid reservoir 22.

The piston cylinders 23 and 24 are connected to the hydraulic fluid reservoir 22 through a conduit 28 and a manifold 29. Connected to manifold 29 by conduit 30a is a first solenoid valve 30 which has a conduit 31 connecting into a T-shaped connection means 32 which serve to connect the piston cylinder 24 by a connection means 33 with the conduit 31 and the manifold 29. The T-shaped member 32 has a conduit 34 connected thereto which in turn, is connected to a second T-shaped member 35 which allows hydraulic fluid to be transmitted to piston cylinder 23 by connection 36. The T-shaped member 35, in turn, is connected by a still further conduit 37 to a second solenoid valve 38 which connects by conduit 39 to manifold 40 which, in turn, connects by conduit 41 to exhaust reservoir 21.

Arranged within the piston cylinders 23 and 24, respectively, are pistons 42 and 43 provided with piston arms or rods 44 and 45 which, in turn, are connected pivotally at points 46 and 47 with spring members 48 and 49 which are in themselves pivotally connected at points 50 and 51 with body member 14 to allow the latter to be moved to the wall of the well-bore 11 as will be described further.

The manifold 29 has connected thereto by conduit 60u a third solenoid valve which is connected by conduit 61 to a passageway 62 and to piston cylinder 15 in the block 16. A conduit 63 connects into a passageway 64 in the block 16 and to piston cylinder 15 and to a fourth solenoid valve 65 which connects by conduit 66 into manifold 40.

A fifth solenoid valve is connected to manifold 29 by conduit 70a and connects by conduit 71 into the piston cylinder 27 as will be seen in the sectional View of Fig. 2. Piston cylinder 27 has arranged in its pistons 72 and 73 which are interconnected by a piston rod 74. It will be noted that piston 72 has an area substantially larger than the area of piston 73 and it will be further noted that the arrangement of conduit 71 allows the hydraulic lluid to be exerted against piston 72. The purpose of pistons 72 and 73 is to allow the drilling mud pressure to be used as a motivating force in actuating piston 17 as will be described. As will be seen, piston cylinder 27 is connected at its smaller end to a conduit 75 which, in turn, connects with a passageway 76 in the block 16 and communicates thereby with the piston cylinder 15. The piston cylinder 27 is also connected at its larger end with conduit 77 which, in turn, connects with a sixth solenoid valve 78 connecting by conduit 79 to manifold 40.

Referring specifically to Fig. 2, it will be noted that the piston 17 is provided with an inner piston 90 which has on a free end thereof a cutting member 91 which is adapted to cut the filter cake 13 sheathing the well bore 11. The piston is arranged in an inner chamber 92 of the piston 17 and communicates with the piston cylinder 15 through an opening 93 in the wall of the piston 17. The piston 17 is suitably sealed by sealing means 94 and 95 while the piston 90 is also provided with seals 96 and 97 for operation thereof.

The piston 17 has adjacent a free end thereof enclosed by the seal 18 a port 100 which communicates with the space 101 enclosed by the seal 18. The port or conduit is connected by a conduit 102 to a seventh solenoid valve 103. This solenoid valve is provided with a bellowstype arrangement 104 in which is positioned an iron rod 105. Spaced above the bellows arrangement is a magnet means 106 which on energization, as will be described, serves to draw the iron rod 105 upwardly and to lift the seating means 106a on the end of the iron rod 105 off the seat 107 in the bellows arrangement 104. It will be noted that the bellows arrangement means 104 is connected by a conduit 108 to an eighth solenoid valve 109 which, in turn, is connected by conduit 110 to the reservoir 26 which carries the uid oxidizing agent.

It will be noted that the cavity 25 is open to the well and that the reservoir 26 may be constructed of a deformable material to allow well pressure to be exerted directly thereon. It is to be further noted that the hydraulic fluid reservoir 22 may likewise be constructed of a deformable material and that the reservoir 22 is also exposed to the well pressure through ports 111 in the body member 14.

The solenoid valves 30, 60 and 70 are connected by electrical conducting means 120, 121 and 122 to electrical energy means not shown at the wellhead and which are carried thereto through electrical conductor 123 which, in turn, connects with the electrical conductor cable 14a. Similarly, the solenoid valves 38, 65 and 78 are also connected by electrical conducting means 124, 125 and 126 to electrical energizing means at the wellhead and carried thereto by electrical conductor 123 and electrical conductor cable 14a. Similarly, the solenoid valve 103 is connected by electrical connecting means 127 to electrical conductor 123 which, in turn, is carried to the earths surface and connected to electrical energizing means, not shown. In a similar manner, the magnetizing means 106 is also connected by electrical connecting means 128 to electrical conductor 123 which is then carried to the wellhead through electrical conductor cable 14a.

Disposed within the lower section of housing 14 and below reservoir 22 is a seismometer 140. The purpose of this seismometer is to detect the elastic waves caused by reaction of the fluid oxidizing agent with petroliferous or organic substances with which the ud oxidizing agent may come into contact when it s released as will be described further. It will be noted that the seismometer is connected by electrical connecting means 141 (see Fig. 3) to electrical conductor 123 and is carried to the earths surface through electrical conductor cable 14a to a conventional recording means (not shown). The seismometer assembly is exposed to well pressure through ports 111 in the housing 14.

Referring now to Fig. 3, a seismic wave detector 140 is shown adapted for use in the practice of my invention under conditions where high hydrostatic pressures exist, as, for example, in deep well bores lilled with water or drilling uid. The numeral 200 designates an elongated tubular element of magnetostrictive metal such as nickel, cobalt, or an alloy of these two metals. Suitably closing one end of element 200 is an end piece 201 preferably made of a non-magnetic metal such as brass. End piece 201 is preferably affixed to element 200 as by silver soldering. However, other means such as screw threads may be employed to join end piece 201 with element 200 and preferably make a uid-tight joint. The other end of element 200 is closed by a non-magnetic metal end piece 202 provided with a central opening 203 for the passage of electrical conductors therethrough. So that elements to be described hereinafter may be placed in or removed from element 200, end piece 202 may be afxed to element 200 by means of a plurality of screws 204. So that fluid will not enter inside element 200 a seal comprising metal spider 205, compressible gasket 206, and plate 207 may be arranged within element 200 and adjacent end piece 202. Cap screws 208, passing through end piece 202,

spider 205, gasket 206, and screw threadedly engaged into plate 207, may be tightened to compress gasket 206 and produce a uid-tight seal with the walls of element 200. Electrically conducting rods 209, having suitable terminal heads 210, may be passed through insulating bushings 211 and 212 arranged on opposite sides of compressible insulating gaskets 213. By tightening nuts 214 threadedly engaged upon rods 209, a fluid-tight seal is provided permitting the electrical connection of conductor cables 141 to elements confined inside the cavity defined by element 200 and end pieces 201 and 202.

Within element 200 is a magnetized bar or plate 217 over which is arranged a coil form 218 made of any suitable electric insulating material such as Bakelite. Coil form 218 is suitably affixed to magnet 217 so that the electrically conducting coil of insulated wire 219 wound thereon is immovable with respect to magnet 217.

Magnet bar 217 may be any permanently magnetizable metal or alloy. If desired bar 217 may be constructed of an alloy which is permanently magnetizable and also is capable of exhibiting magneto-strictive properties.

The apparatus of our invention works in the following manner: It may be assumed that the body member 14 is lowered in the well bore 11 to a point adjacent the formation 12 traversed by the well bore and it is desired to determine whether or not the formation 12 contains petroliferous or organic substances and the like. When the body member 14 has reached a desired point in the well bore traversing formation 12, the solenoid valve 30 is opened allowing the pressure exerted on the deformable bag reservoir 22 containing hydraulic oil to cause the hydraulic oil to ow into the piston cylinders 23 and 24. Since the areas of pistons 42 and 43 are greater than the cross sectional areas of the piston rods 44 and 45 which are exposed to well pressure, the hydraulic oil in bag 22 causes the pistons 42 and 43 to move, respectively, upwardly and downwardly, which causes spring members 48 and 49 to be compressed which positions the body member 14 against a wall of the well bore 11 as shown in Figs. 1 and 2. The solenoid valve 30 is closed after the body member has been moved against the wall of the well bore. Solenoid valve 70 is then opened by proper energization which causes hydraulic fluid to be exerted against the area of piston 72. The hydraulic fluid back of piston 73 is caused to flow through conduit 75 into piston cylinder 15 exerting a force on the piston 17 and causing it to move to the right and providing a seal by the deformable member 18 with the filter cake 13. Thereafter the solenoid valve 60 is energized which allows hydraulic fluid to move into the piston cylinder 15 through conduit 61 and pass through passageway 93 into the inner chamber 92 of piston member 17. This causes a force to be exerted against the piston 90 and moves it to the right and causes the cutting edge 91 to penetrate the filter cake 13.

After the filter cake has been cut by the cutting member 91, the solenoid valve 60 is closed and the solenoid valve 65 is opened allowing the hydraulic oil in the inner chamber 92 to be released through conduit 63 into reservoir 21 through conduit 66, manifold 40 and conduit 41. As a result of the pressure being released into reservoir 21 the formation pressure is exerted against the piston 90 which causes it to be moved to the left within the chamber 92. Thus the formation 12 is now exposed and any hydrocarbons or petroliferous substances and the like contained in the formation 12 may be contacted with the uid oxidizing agent as will be described.

After the sequence of operations has been conducted as described, the solenoid valve 109 is opened and magnet means 106 is energized. As the magnet means is energized the iron rod 105 is caused to move upward in the bellows arrangement 104 which lifts the seating member 106:1 off the seat 107. Valve 109 is then closed and solenoid valve 103 is opened. Magnet means 106 is then deenergized allowing member 106a to seat on seat 107. Solenoid valve 103 is then closed. Since the drilling mud pressure exerted on bag 26 is greater than formation pressure the lluid oxidizing medium is caused to flow, in the sequence described, through conduits 110, 108 and 102 into the area 101 enclosed by the sealing means 18 and thence into contact with formation 12 which has been exposed by the cutting edge 91. Thus, the oxidizing agent may be injected in controlled amounts. As a result of contact of the oxidizing agent with the formation 12, a reaction ensues between the oxidizing agent and any petroliferous or organic substances in the formation 12. This reaction causes heat to be liberated and also causes the generation of elastic waves. The elastic waves are detected by seismometer and recorded at the surface. Thereafter, when it is desired to move the device to a new location for testing the formation, the pressure exerted against pistons 42 and 43 is released by opening solenoid valve 38 and releasing pressure through manifold 40 and thence into exhaust reservoir 21. This frees the body member 14 and allows it to resume a normal position in the well. The piston member 17 may be retracted by opening solenoid valve 78 which releases hydraulic fluid from the piston cylinder 27 releasing the piston 17 and allowing it to move to the left. When it is desired to test another formation or position in the well bore the sequence of operations may be repeated.

A pressure type seismometer such as described in connection with Fig. 3 is a preferred seismometer. A pressure seismometer is insensitive to motion and hence is more desirable than displacement type seismometers, which are responsive to motion, for use in the continuous logging described with this method.

A displacement type seismometer rather than the described pressure type, could also be utilized in the logger, but may require that the logger be stopped and be allowed to come to rest prior to a test.

Under some conditions, the reaction may be sufficiently great in magnitude to be detected by a seismometer located at the surface of the earth. This invention, therefore, is not limited in its application to a seismometer located within the housing 14.

The nature and objects of the present invention having been completely described and illustrated, what we desire to claim as new and useful and to secure by Letters Patent is:

1. A method for detecting the presence of a petroliferous substance in an earth formation penetrated by a well bore produced by a drilling method which deposits a filter cake lining which comprises disrupting filter cake from a portion of the face of said formation in the borehole, introducing perchloric acid into said well bore, contacting it with at least a portion of the formation from which said filter cake has been so disrupted and there reacting said perchloric acid with said substance, obtaining an electric signal from sound waves produced by the reaction, transmitting said electric signal to the surface of the earth and there displaying a function of said signal.

2. A method for detecting the presence of a petroliferous substance in an earth formation penetrated by a well bore produced by a drilling method which deposits a lter cake lining on said well bore which comprises disrupting filter cake from a portion of the face of said formation in the borehole, introducing a solution of perchloric acid having a strength in the range between 70% and 84% HC1O4 into said well bore, contacting said solution with at least a portion of the formation from which the filter cake has been so disrupted and there reacting said perchloric acid solution with said substance in the presence of ceric ammonium nitrate to cause a shock wave in that portion of the formation from which the lter cake has been disrupted, obtaining anl electric signal from said reaction, transmitting said electric signal to the surface of the earth and there displaying a function of said signal whereby the presence of said substance is indicated.

3. A method for prospecting in a well bore penetrating an earth formation containing carbonaceous matter and produced by a drilling method which deposits a lter cake lining on the well bore which comprises disrupting lter cake from a portion of the face of said formation in the borehole, contacting at least a portion of the formation from which said lter cake has been so disrupted with an oxidizing agent reactable with carbonaceous matter in said formation, reacting said oxidzing agent and said carbonaceous matter to generate an explosive shock wave, detecting said explosive shock wave with a seismic detector to obtain an electric signal from said detector in response to said reaction, transmitting said electric signal to the surface of the earth and there displaying a function of said signal whereby the presence of said carbonaceous matter is indicated.

4. A method for prospecting in a well bore penetrating an earth formation containing carbonaceous matter and produced by a drilling method which deposits a lter cake lining on the well bore which comprises disrupting filter cake from a portion of the face of said formation in the borehole, contacting at least a portion of the formation from which said lter cake has been so disrupted with an oxidizing agent reactable with carbonaceous matter in said formation, reacting said oxidizing agent and said carbonaceous matter to generate an explosive pressure wave, detecting said explosive pressure wave with a pressure detector to obtain an electric signal from said detector in response to said reaction, transmitting said electric signal to the surface of the earth and there displaying a function of said signal whereby the presence of said carbonaceous matter is indicated.

No references cited. 

2. A METHOD FOR DETECTING THE PRESENCE OF A PETROLIFEROUS SUBSTANCE IN AN EARTH FORMATION PENETRATED BY A WELL BORE PRODUCED BY A DRILLING METHOD WHICH DEPOSITS A FILTER CAKE LINING ON SAID WELL BORE WHICH COMPRISES DISRUPTING FILTER CAKE FROM A PORTION OF THE FACE OF SAID FORMATION IN THE BOREHOLE, INTRODUCING A SOLUTION OF PERCHLORIC ACID HAVING A STRENGTH IN THE RANGE BETWEN 70% AND 84% HCLO4 INTO SAID WELL BORE, CONTACTING SAID SOLUTION WITH AT LEAST A PORTION OF THE FORMATION FROM WHICH THE FILTER CAKE HAS BEEN SO DISRUPTED AND THERE REACTING SAID PERCHLORIC ACID SOLUTION WITH SAID SUBSTANCE IN THE PRESENCE OF CERIC AMMONIUM NITRATE TO CAUSE A SHOCK WAVE IN THAT PORTION OF THE FORMATION FORM WHICH THE FILTER CAKE HAS BEEN DISTRUPTED, OBTAINING AN ELECTRIC SIGNAL FROM SAID REACTION, TRANSMITTING SAID ELECTRIC SIGNAL TO THE SURFACE OF THE EARTH AND THERE DISPLAYING A FUNCTION OF SAID SIGNAL WHEREBY THE PRESENCE OF SAID SUBSTANCE IS INDICATED. 